Photosensitive polymides

ABSTRACT

The invention pertains to an isocyanate-modified photosensitive polyimide. The photosensitive polyimide of the invention possesses excellent heat resistance, chemical resistance and flexibility, and can be used in a liquid photo resist composition or dry film photo resist composition, or used in a solder resist, coverlay film, or printed wiring board.

FIELD OF THE INVENTION

The invention relates to an isocyanate-modified photosensitivepolyimide. The photosensitive polyimide of the invention possessesexcellent heat resistance, chemical resistance and flexibility, and canbe used in a liquid photo resist composition or dry film photo resistcomposition, or used in a solder resist, coverlay film, or printedwiring board.

BACKGROUND OF THE INVENTION

Electronic products recently have more and more miniaturized and lighterin weight. In accordance with this, various electronic parts arerequired to be downsized. Based on the ground that flexible printedwiring boards have the advantage of flexibility and light weight, theirdemand greatly increases.

With respect to the materials used, coverlay films can be divided intothe following three types: photosensitive coverlay film (first type),non-photosensitive coverlay film (second type) and thermal plasticcoverlay film (third type). The photosensitive coverlay film (firsttype) also can be divided into polyimide based coverlay film (PI basedcoverlay film) and non-polyimide based coverlay film (non-PI basedcoverlay film). Since the non-PI based coverlay film has poor heatresistance, higher coefficient of thermal expansion (CTE), etc., henceits applications are more restricted. The non-photosensitive coverlayfilm (second type) is more complex in process than is the photosensitivecoverlay film (first type), and thus the practicability of thenon-photosensitive coverlay film is inferior to that of thephotosensitive coverlay film. As for the thermal plastic coverlay film,a holes-formation operation as a post-process is needed, and thereforein the respect of the convenience, the thermal plastic coverlay film isinferior to the photosensitive coverlay film.

U.S. Pat. No. 6,605,353 has disclosed an epoxy-modified photosensitivepolyimide. The epoxy-modified photosensitive polyimide is prepared byreacting an epoxide with an acid. However, based on the ground that OHfunctional groups generated after ring-opening reaction can then reactwith epoxy groups, the epoxy-modified photosensitive polyimideaccordingly has the problems of storage-stability and heat-stability.

In order to improve the heat resistance and process convenience, thereis a desire to find a novel photosensitive polyimide which can overcomethe above-mentioned problems.

SUMMARY OF THE INVENTION

The invention provides an isocyanate-modified photosensitive polyimide,which possesses excellent stability and heat stability, and in additioncan be cured at a low temperature.

The invention further provides a photosensitive composition comprisingthe photosensitive polyimide mentioned above, which can be used as aprotective film material or can be used in a photo resist composition.The film formed from the photosensitive composition of the inventionpossesses excellent electrical properties, heat resistance, flexibilityand chemical resistance. As a consequence, the photosensitivecomposition of the invention can be used in a solder resist for aprotective film material, a coverlay film and a printed circuit board.

DETAILED DESCRIPTION OF THE INVENTION

The photosensitive polyimide of the invention has a structurerepresented by formula (I):

wherein

-   -   B and D are the same or different, and each independently is a        divalent organic group;    -   A is a tetravalent organic group containing at least one        modifying group R′, J is a tetravalent organic group without a        modifying group R′, n is an integer of 0 or greater than 0, and        m is an integer of greater than 0.    -   R′ is selected from the following groups:

wherein R is a vinyl-containing unsaturated group or is a group selectedfrom:

wherein

-   -   R1 is a substituted or unsubstituted C1-C20 saturated or        unsaturated organic group;    -   R2 is a vinyl-containing unsaturated group.

It is preferable that the vinyl-containing unsaturated group, asmentioned above, is selected from:

wherein

-   -   each of R4 and R5 is independently H or a substituted or        unsubstituted C1-C5 alkyl group, and    -   R6 is a covalent bond or is a substituted or unsubstituted        C1-C20 organic group.

It is more preferable that the vinyl-containing unsaturated group, asmentioned above, is independently selected from the group consisting of:

wherein z is an integer of 0-6.

It is especially preferable that the vinyl-containing unsaturated group,as mentioned above, is independently selected from the group consistingof:

wherein z is an integer of 0-6.

Preferably, R1 is a group selected from the following groups:

wherein

-   -   o, p, q and r are each independently an integer of 0 or greater        than 0;    -   R4, R5 and R6 have the same meaning as defined above;    -   R7 is H or substituted or unsubstituted C1-C12 organic group ;        and    -   R8 is a covalent bond or an organic group selected from:

More preferably, R1 is a group selected from the following groups:

There is no particular restriction on the divalent organic group B and Dcontained in the photosensitive polyimide of formula (I) of theinvention, which for example, may be a divalent aromatic group, adivalent aliphatic group or a divalent group containing a siloxy group.Preferably, B and D are each independently selected from the groupconsisting of:

wherein

-   -   R″ is —H, C1-C4 alkyl, C1-C4 perfluoroalkyl, methoxy, ethoxy,        halogen, OH, COOH, NH₂ or SH;    -   R9 is H, methyl or ethyl;    -   c is an integer of 0-4;    -   d is an integer of 0-4;    -   a is an integer of greater than 0;    -   b is an integer of greater than 0; and    -   each R11 is a covalent bond or a group selected from the        following groups:

wherein

-   -   w and x are each independently an integer of greater than 0; and    -   R12 is —S(O)₂−, —C(O)—, a covalent bond or a substituted or        unsubstituted C1-C18 organic group.

More preferably, B and D in formula (I) are each independently selectedfrom the group consisting of:

wherein y is an integer of 1-12, preferably an integer of 1-6.

In the photosensitive polyimide of formula (I) of the invention, A isderived from acid anhydride having reactive functional groups includingOH, COOH or NH₂. It is preferable that each A is independent selectedfrom the group consisting of:

wherein

-   -   R′ is an organic group selected from:

wherein R has the same meaning as defined above;

-   -   R₁₃ is —CH₂—, —O—, —S—, —CO—, —SO₂—, —C(CH₃)₂— or —C(CF₃)₂—;    -   R₁₄ is —H or —CH₃—;    -   X is —O—, —NH— or —S—.

It is more preferable that each A is independent selected from the groupconsisting of:

wherein R′ has the same meaning as defined above.

In the photosensitive polyimide of formula (I) of the invention, J is agroup derived from an acid anhydride monomer, which can be with orwithout reactive functional groups. It is preferable that J is selectedfrom the group consisting of:

wherein

-   -   R₁₅ is OH, COOH or NH₂;    -   R₁₃ is —CH₂—, —O—, —S—, —CO—, —SO₂—, —C(CH₃)₂— or —C(CF₃)₂—;    -   R₁₄ is —H or —CH₃—;    -   X is —O—, —NH— or —S—.

It is more preferably that J in formula (I) is selected from the groupconsisting of:

The photosensitive polyimide of the invention can be prepared by theconventional polymerization methods known by people having ordinaryknowledge in the same field. For example, the photosensitive polyimidecan be prepared by a method comprising:

-   -   (a) reacting a diamine monomer having formula H₂N—P—NH₂ with a        dianhydride monomer having formula

and another dianhydride having formula

to form a compound having formula (1):

wherein G is a reactive functional group such as OH, COOH or NH₂.

Taking COOH as an example, the next reaction step comprises:

-   -   (b) adding the product of step (a) to an isocyanate compound        having formula O═C═N—R to form a compound of formula (2),

wherein f+g=i∘

The method for preparing photosensitive polyimide, as mentioned above,can utilize the acid anhydride monomer having reactive functional groupsof the invention, which is selected from the group consisting of:

wherein

-   -   R₁₅ is OH, COOH or NH₂;    -   R₁₃ is —CH₂—, —O—, —S—, —CO—, —SO₂—, —C(CH₃)₂— or —C(CF₃)₂—;    -   R₁₄ is —H or —CH₃—;    -   X is —O—, —NH— or —S—.

Preferably, the acid anhydride having reactive functional groups, usedin the invention, can be selected from the group consisting of:

Though there is no particular restriction, another acid anhydride usedin the method for preparing the photosensitive polyimide, as mentionedabove, can be with or without reaction functional groups. The acidanhydride without bearing reaction functional groups, used in theinvention, are known by people skilled in the same field, and can be,for example, but not limited to:

wherein

-   -   E, F and H are each independently a covalent bond or a        substituted or unsubstituted C1-C20 saturated or unsaturated,        cyclic or non-cyclic organic group; R3 is a covalent bond or is        selected from the following groups:

Preferably, the another acid anhydride monomer used in the invention canbe selected from the group consisting of:

The diamine monomer used in the method for preparing the photosensitivepolyimide, as mentioned above, generally can be aliphatic, aromatic orsiloxy-containing divalent groups. Preferably, the diamine monomercomprises, but is not limited to, the following structures:

wherein

-   -   R″ is —H, C1-C4 alkyl, C1-C4 perfluoroalkyl, methoxy, ethoxy,        halogen, OH, COOH, NH₂ or SH;    -   R9 is H, methyl or ethyl;    -   c is an integer of 0-4;    -   d is an integer of 0-4;    -   a is an integer of greater than 0;    -   b is an integer of greater than 0; and    -   R11 are each independently a covalent bond or a group selected        from the following groups:

wherein

-   -   w and x are each independently an integer of greater than 0; and    -   R12 is —S(O)₂—, —C(O)—, a covalent bond or a substituted or        unsubstituted C1-C18 organic group.

Preferably, the diamine monomer can be selected from the groupconsisting of the following compounds:

wherein y is an integer of 1-12, preferably an integer of 1-6.

In order to impart polyimides with a photosensitive group so thatradiation curing mechanism can be utilized, the present inventionmodifies polyimides with an isocyanate having a photosensitive group,such as as C═C group. The isocyanates can be mono-isocyanates ordi-isocyanates, preferably mono-isocyanates. The isocyanates used in theinvention can react with reactive groups,such as hydroxyl (—OH), carboxy(—COOH), amino (—NH₂), etc, in the polyimides and thus makes thepolyimides modified. The isocyanate used in the invention has thestructure O═C═N—R, wherein R is R* or a group having the followingstructures:

wherein

-   -   R* and R2 are each independently a photosensitive group of        vinyl-containing unsaturated group; and    -   R1 is a substituted or unsubstituted C1-C20 saturated or        unsaturated organic group.

According to an embodiment of the invention, the vinyl-containingunsaturated group is selected from the following groups:

wherein

-   -   R4 and R5 are each independently H or a substituted or        unsubstituted C1-C5 alkyl group, and    -   R6 is a covalent bond or substituted or unsubstituted C1-C20        organic group;        -   R1 is a group selected from the following groups:

wherein

-   -   o, p, q and r are each independently an integer of 0 or greater        than 0;    -   R4, R5 and R6 have the same meaning as defined above;    -   R7 is H or a substituted or unsubstituted C1-C12organic group;        and    -   R8 is a covalent bond or an organic group selected from:

The invention further provides a photosensitive composition, whichcomprises at least 1% by weight of the photosensitive polyimide offormula (I), a photoinitiator and a solvent. The photosensitivecomposition of the invention can be used in a liquid photo resistcomposition or dry film photo resist composition, or used in a solderresist, coverlay film or printed wiring board. The weight percentage ofthe components in the photosensitive composition can be modifieddepending on the product demand. Generally, the amount of thephotosensitive polyimide, based on the total weight of the composition,is at least 1% by weight, preferably between 10 and 50% by weight. Theamount of the photoinitiator based on the total weight of thecomposition is at least 0.001% by weight, preferably between 0.01 to 1%by weight.

There is no particular restriction on the photoinitiator used for thephotosensitive composition. Examples of the photoinitiator are selectedfrom the group consisting of: benzophenone, benzoin,2-hydroxy-2-methyl-1-phenyl-propan-1-one,2,2-dimethoxy-1,2-diphenylethan-1-one, 1-hydroxy cyclohexyl phenylketone, 2,4,6-trimethylbenzoyl diphenyl phosphine oxide,N-phenylglycine, 9-phenylacridine, benzyldimethylketal,4,4′-bis(diethylamino)benzophenone, 2,4,5-triarylimidazole dimmers andmixtures thereof. Preferably, the photoinitiator is2,4,6-trimethylbenzoyl diphenyl phosphine.

According to the invention, there is no particular restriction on thesolvent used for the photosensitive composition. For example, thesolvent may be selected from the group consisting of, but not limitedto: N-methylpyrrolidone (NMP), dimethyl acetamide (DMAC), dimethylformamide (DMF), dimethyl sulfoxide (DMSO), toluene, xylene and mixturesthereof.

In order to increase the degree of photo-crosslinking, thephotosensitive composition of the present invention optionally comprisesa certain amount of a reactive monomer or short-chain oligomer formaking the molecules crosslinked. According to the invention, there isno particular restriction on the reactive monomer or short-chainoligomer used for the photosensitive composition. For example, thereactive monomers or short-chain oligomers may be selected from thegroup consisting of: 1,6-hexanediol diacrylate, neopentyl glycoldiacrylate, ethylene glycol diacrylate, pentaerythritol diacrylate,trimethylolpropane triacrylate, pentaerythritol triacrylate,dipentaerythritol hexaacrylate, tetramethylolpropane tetraacrylate,tetraethylene glycol diacrylate, 1,6-hexanediol dimethacrylate,neopentyl glycol dimethacrylate, ethylene glycol dimethacrylate,pentaerythritol dimethacrylate, trimethylolpropane trimethacrylate,pentaerythritol trimethacrylate, dipentaerythritol hexamethacrylate,tetramethylolpropane tetramethacrylate, tetraethylene glycoldimethacrylate, methoxydiethylene glycol methacrylate,methoxypolyethylene glycol methacrylate,β-methacryloyloxyethylhydrodiene phthalate,β-methacryloyloxyethylhydrodiene succinate, 3-chloro-2-hydroxypropylmethacrylate, stearyl methacrylate, phenoxyethyl acrylate,phenoxydiethylene glycol acrylate, phenoxypolyethylene glycol acrylate,β-acryloyloxyethylhydrodiene succinate, lauryl acrylate, ethylene glycoldimethacrylate, diethylene glycol dimethacrylate, triethylene glycoldimethacrylate, polyethylene glycol dimethacrylate, 1,3-butylene glycoldimethacrylate, polypropylene glycol dimethacrylate,2-hydroxy-1,3-dimethacryloxypropane, 2,2-bis[4-(methacryloxyethoxy)phenyl]propane, 2,2-bis[4-(methacryloxydiethoxy)phenyl]propane,2,2-bis[4-(methacryloxypolyethoxy)phenyl]propane, polyethylene glycoldiacrylate, tripropylene glycol diacrylate, polypropylene glycoldiacrylate, 2,2-bis[4-(acryloxydiethoxy)phenyl]propane,2,2-bis[4-(acryloxypolyethoxy) phenyl]propane,2-hydroxy-1-acryloxy-3-methacryloxypropane, trimethylolpropanetrimethacrylate, tetramethylolmethane triacrylate, tetramethylolmethanetetraacrylate, methoxydipropylene glycol methacrylate,methoxytriethylene glycol acrylate, nonylphenoxypolyethylene glycolacrylate, nonylphenoxypolypropylene glycol acrylate,1-acryloyloxypropyl-2-phthalate, isostearyl acrylate, polyoxyethylenealkyl ether acrylate, nonylphenoxyethylene glycol acrylate,polypropylene glycol dimethacrylate, 1,4-butanediol dimethacrylate,3-methyl-1,5-pentanediol dimethacrylate, 1,6-hexanediol methacrylate,1,9-nonanediol methacrylate, 2,4-diethyl-1,5-pentanediol dimethacrylate,1,4-cyclohexanedimethanol dimethacrylate, dipropylene glycol diacrylate,tricyclodecanedimethanol diacrylate, 2,2-hydrogenatedbis[4-acryloxypolyethoxy]phenyl)propane,2,2-bis[4-acryloxypolypropoxy]phenyl)propane,2,4-diethyl-1,5-pentanediol diacrylate, ethoxylated trimethylolpropanetriacrylate, propoxylated trimethylolpropane triacrylate, isocyanuricacid tri(ethaneacrylate), pentaerythritol tetraacrylate, ethoxylatedpentaerythritol tetraacrylate, propoxylated pentaerythritoltetraacrylate, ditrimethylolpropane tetraacrylate, dipentaerythritolpolyacrylate, triallyl isocyanurate, glycidyl methacrylate, allylglycidyl ether, 1,3,5-triacryloylhexahydro-s-triazine, triallyl1,3,5-benzenecarboxylate, triallylamine, triallyl citrate, triallylphosphate, allobarbital, diallylamine, diallyldimethylsilane, diallyldisulfide, diallyl ether, diallyl cyanurate, diallyl isophthalate,diallyl terephthalate, 1,3-diallyloxy-2-propanol, diallyl sulfide,diallyl maleate, 4,4′-isopropylidenediphenol dimethacrylate,4,4′-isopropylidenediphenol diacrylate and mixtures thereof. When thereactive monomer or oligomer are present in the photosensitivecomposition of the invention, the amount of the reactive monomer oroligomer, based on the total weight of the composition, is at least 0.1%by weight, preferably 0.1-30% by weight.

The invention is further described with reference to the followingExamples, to which the invention is not limited. Various modificationsand variations made by any one familiar with the technical field of theinvention without violating the spirit of the invention, are within thescope of the invention.

EXAMPLES

The abbreviations used in the following Examples are defined below:

-   6FDA: 4,4′-hexafluoroisopropylidene-2,2-bis-(phthalic acid    anhydride)-   DMDB: 2,2′-dimethylbiphenyl-4,4′-diamine-   ODA: 4,4′-oxydibenzenamine-   2-IEA: 2-isocyanatoethyl acrylate-   1-MI: 1-methylimidazole-   PTZ: phenothiazine-   DMAC: dimethyl acetamide-   NMP: N-methylpyrrolidone

Example 1 Synthesis of isocyanate-modified polyimide (P1)

To weighed 64.85 g (0.2 mol) of DA1 and 42.46 g (0.2 mol) of DMDB, 300mL of NMP was added. The mixture was stirred at room temperature for 1hour, and then successively heated to 50° C. and stirred for 4 hours.After 4 hours, 50 mL of toluene was added. The resulting solution wasdehydrated with the Dean-Stark apparatus at 130° C. After thedehydration was complete, the solution was cooled to room temperaturefollowed by the addition of 7 g (0.05 mol) of 2-IEA, 0.05g of 1-MI and0.06 g of PTZ. After the addition was complete, the solution was heatedto 80° C. and stirred for 8 hours. Then, P1 was obtained.

Example 2 Synthesis of isocyanate-modified polyimide (P2)

To weighed 73.256 g (0.2 mol) of DA2 and 42.46 g (0.2 mol) of DMDB, 350mL of NMP was added. The mixture was stirred at room temperature for 1hour, and then successively heated to 50° C. and stirred for 4 hours.After 4 hours, 50 mL of toluene was added. The resulting solution wasdehydrated with the Dean-Stark apparatus at 130° C. After thedehydration was complete, the solution was cooled to room temperaturefollowed by the addition of 7 g (0.05 mol) of 2-IEA, 0.05g of 1-MI and0.06 g of PTZ. After the addition was complete, the solution was heatedto 80° C. and stirred for 8 hours. Then, P2 was obtained.

Example 3 Synthesis of isocyanate-modified polyimide (P3)

To weighed 100.074 g (0.2 mol) of DA3 and 42.46 g (0.2 mol) of DMDB, 450mL of NMP was added. The mixture was stirred at room temperature for 1hour, and then successively heated to 50° C. and stirred for 4 hours.After 4 hours, 50 mL of toluene was added. The resulting solution wasdehydrated with the Dean-Stark apparatus at 130° C. After thedehydration was complete, the solution was cooled to room temperaturefollowed by the addition of 7 g (0.05 mol) of 2-IEA, 0.05g of 1-MI and0.06 g of PTZ. After the addition was complete, the solution was heatedto 80° C. and stirred for 8 hours. Then, P3 was obtained.

Example 4 Synthesis of isocyanate-modified polyimide (P4)

To weighed 124.1 g (0.2 mol) of DA4 and 42.46 g (0.2 mol) of DMDB, 550mL of NMP was added. The mixture was stirred at room temperature for 1hour, and then successively heated to 50° C. and stirred for 4 hours.After 4 hours, 50 mL of toluene was added. The resulting solution wasdehydrated with the Dean-Stark apparatus at 130° C. After thedehydration was complete, the solution was cooled to room temperaturefollowed by the addition of 14 g (0.1 mol) of 2-IEA, 0.1 g of 1-MI and0.12 g of PTZ. After the addition was complete, the solution was heatedto 80° C. and stirred for 8 hours. Then, P4 was obtained.

Example 5 Synthesis of isocyanate-modified polyimide (P5)

To weighed 126.9 g (0.2 mol) of DA5 and 42.46 g (0.2 mol) of DMDB, 550mL of NMP was added. The mixture was stirred at room temperature for 1hour, and then successively heated to 50° C. and stirred for 4 hours.After 4 hours, 50 mL of toluene was added. The resulting solution wasdehydrated with the Dean-Stark apparatus at 130° C. After thedehydration was complete, the solution was cooled to room temperaturefollowed by the addition of 14 g (0.1 mol) of 2-IEA, 0.1 g of 1-MI and0.12 g of PTZ. After the addition, the solution was heated to 80° C. andstirred for 8 hours. Then, P5 was obtained.

Example 6 Synthesis of isocyanate-modified polyimide (P6)

To weighed 115.7 g (0.2 mol) of DA6 and 42.46 g (0.2 mol) of DMDB, 500mL of NMP was added. The mixture was stirred at room temperature for 1hour, and then successively heated to 50° C. and stirred for 4 hours.After 4 hours, 50 mL of toluene was added. The resulting solution wasdehydrated with the Dean-Stark apparatus at 130° C. After thedehydration was complete, the solution was cooled to room temperaturefollowed by the addition of 7 g (0.05 mol) of 2-IEA, 0.05 g of 1-MI and0.06 g of PTZ. After the addition was complete, the solution was heatedto 80° C. and stirred for 8 hours. Then, P6 was obtained.

Example 7 Synthesis of isocyanate-modified polyimide (P7)

To weighed 64.85 g (0.2 mol) of DA1 and 40.05 g (0.2 mol) of ODA, 300 mLof DMAC was added. The mixture was stirred at room temperature for 1hour, and then successively heated to 50° C. and stirred for 4 hours.After 4 hours, 50 mL of toluene was added. The resulting solution wasdehydrated with the Dean-Stark apparatus at 130° C. After thedehydration was complete, the solution was cooled to room temperaturefollowed by the addition of 7 g (0.05 mol) of 2-IEA, 0.05 g of 1-MI and0.06 g of PTZ. After the addition, the solution was heated to 80° C. andstirred for 8 hours. Then, P7 was obtained.

Example 8 Synthesis of isocyanate-modified polyimide (P8)

To weighed 73.26 g (0.2 mol) of DA2 and 40.05 g (0.2 mol) of ODA, 350 mLof DMAC was added. The mixture was stirred at room temperature for 1hour, and then successively heated to 50° C. and stirred for 4 hours.After 4 hours, 50 mL of toluene was added. The resulting solution wasdehydrated with the Dean-Stark apparatus at 130° C. After thedehydration was complete, the solution was cooled to room temperaturefollowed by the addition of 7 g (0.05 mol) of 2-IEA, 0.05 g of 1-MI and0.06 g of PTZ. After the addition, the solution was heated to 80° C. andstirred for 8 hours. Then, P8 was obtained.

Example 9 Synthesis of isocyanate-modified polyimide (P9)

To weighed 100.074 g (0.2 mol) of DA3 and 40.05 g (0.2 mol) of ODA, 450mL of DMAC was added. The mixture was stirred at room temperature for 1hour, and then successively heated to 50° C. and stirred for 4 hours.After 4 hours, 50 mL of toluene was added. The resulting solution wasdehydrated with the Dean-Stark apparatus at 130° C. After thedehydration was complete, the solution was cooled to room temperaturefollowed by the addition of 7 g (0.05 mol) of 2-IEA, 0.05 g of 1-MI and0.06 g of PTZ After the addition, the solution was heated to 80° C. andstirred for 8 hours. Then, P9 was obtained.

Example 10 Synthesis of isocyanate-modified polyimide (P10)

To weighed 124.1 g (0.2 mol) of DA4 and 40.05 g (0.2 mol) of ODA, 550 mLof DMAC was added. The mixture was stirred at room temperature for 1hour, and then successively heated to 50° C. and stirred for 4 hours.After 4 hours, 50 mL of toluene was added. The resulting solution wasdehydrated with the Dean-Stark apparatus at 130° C. After thedehydration was complete, the solution was cooled to room temperaturefollowed by the addition of 14 g (0.1 mol) of 2-IEA, 0.1 g of 1-MI and0.12 g of PTZ. After the addition, the solution was heated to 80° C. andstirred for 8 hours. Then, P10 was obtained.

Example 11 Synthesis of isocyanate-modified polyimide (P11)

To weighed 126.9 g (0.2 mol) of DA4 and 40.05 g (0.2 mol) of ODA, 550 mLof DMAC was added. The mixture was stirred at room temperature for 1hour, and then successively heated to 50° C. and stirred for 4 hours.After 4 hours, 50 mL of toluene was added. The resulting solution wasdehydrated with the Dean-Stark apparatus at 130° C. After thedehydration was complete, the solution was cooled to room temperaturefollowed by the addition of 14 g (0.1 mol) of 2-IEA, 0.1 g of 1-MI and0.12 g of PTZ. After the addition, the solution was heated to 80° C. andstirred for 8 hours. Then, P11 was obtained.

Example 12 Synthesis of isocyanate-modified polyimide (P12)

To weighed 115.7 g (0.2 mol) of DA4 and 40.05 g (0.2 mol) of ODA, 550 mLof DMAC was added. The mixture was stirred at room temperature for 1hour, and then successively heated to 50° C. and stirred for 4 hours.After 4 hours, 50 mL of toluene was added. The resulting solution wasdehydrated with the Dean-Stark apparatus at 130° C. After thedehydration was complete, the solution was cooled to room temperaturefollowed by the addition of 7 g (0.05 mol) of 2-IEA, 0.05 g of 1-MI and0.06 g of PTZ. After the addition, the solution was heated to 80° C. andstirred for 8 hours. Then, P12 was obtained.

Example 13 Synthesis of isocyanate-modified polyimide (P13)

To weighed 57.85 g (0.1 mol) of DA4, 44.42 g(0.1 mol) of 6FDA and 40.05g (0.2 mol) of ODA, 500 mL of DMAC was added. The mixture was stirred atroom temperature for 1 hour, and then successively heated to 50° C. andstirred for 4 hours. After 4 hours, 50 mL of toluene was added. Theresulting solution was dehydrated with the Dean-Stark apparatus at 130°C. After the dehydration was complete, the solution was cooled to roomtemperature followed by the addition of 7 g (0.05 mol) of 2-IEA, 0.05 g1-MI and 0.06 g of PTZ. After the addition, the solution was heated to80° C. and stirred for 8 hours. Then, P13 was obtained.

Example 14 Synthesis of isocyanate-modified polyimide (P14)

To weighed 63.45 g (0.1 mol) of DA5, 44.42 g(0.1 mol) of 6FDA and 40.05g (0.2 mol) of ODA, 500 mL of DMAC was added. The mixture was stirred atroom temperature for 1 hour, and then successively heated to 50° C. andstirred for 4 hours. After 4 hours, 50 mL of toluene was added. Theresulting solution was dehydrated with the Dean-Stark apparatus at 130°C. After the dehydration was complete, the solution was cooled to roomtemperature followed by the addition of 7 g (0.05 mol) of 2-IEA, 0.05 gof 1-MI and 0.06 g of PTZ. After the addition, the solution was heatedto 80° C. and stirred for 8 hours. Then, P14 was obtained.

1. A photosensitive polyimide having a structure represented by formula(I):

wherein B and D are the same or different, and each independently is adivalent organic group; A is a tetravalent organic group containing atleast one modifying group R′, J is a tetravalent organic group without amodifying group R′, n is an integer of 0 or greater than 0, and m is aninteger of greater than 0, R′ is a group selected from:

wherein R is a vinyl-containing unsaturated group or a group selectedfrom:

wherein R1 is a substituted or unsubstituted C1-C20 saturated orunsaturated organic group; and R2 is a vinyl-containing unsaturatedgroup.
 2. The photosensitive polyimide according to claim 1, wherein thevinyl-containing unsaturated group is selected from the followinggroups:

wherein each of R4 and R5 is independently H or a substituted orunsubstituted C1-C5 alkyl group, and R6 is a covalent bond or asubstituted or unsubstituted C1-C20organic group.
 3. The photosensitivepolyimide according to claim 1, wherein the vinyl-containing unsaturatedgroup is selected from the following groups:

wherein z is an integer of 0-6.
 4. The photosensitive polyimideaccording to claim 1, wherein RI is selected from the following groups:

wherein o, p, q and r are each independently an integer of 0 or greaterthan 0; R4, R5 and R6 have the same meaning as defined in claim 2; R7 isH or a substituted or unsubstituted C1-C12 organic group; and R8 is acovalent bond or an organic group selected from:


5. The photosensitive polyimide according to claim 4, wherein R1 is agroup selected from:


6. The photosensitive polyimide according to claim 1, wherein A isselected from the group consisting of:

wherein R′ has the same meaning as defined in claim 1; R₁₃ is —CH₂—,—O—, —S—, —CO—, —SO₂—, —C(CH₃)₂— or —C(CF₃)₂—; R₁₄ is —H or —CH₃—; X is—O—, —NH— or —S—.
 7. The photosensitive polyimide according to claim 1,wherein A is selected from the group consisting of:

wherein R′ has the same meaning as defined in claim
 1. 8. Thephotosensitive polyimide according to claim 1, wherein J is selectedfrom the group consisting of:

wherein R₁₃, R₁₄ and X have the same meaning as defined in claim 6; R₁₅is OH, COOH or NH₂.
 9. The photosensitive polyimide according to claim1, wherein J is selected from the group consisting of:


10. The photosensitive polyimide according to claim 1, wherein B and Dare the divalent organic group selected from the group consisting of:

wherein R″ is —H, C1-C4 alkyl, C1-C4 perfluoroalkyl, methoxy, ethoxy,halogen, OH, COOH, NH₂ or SH; R9 is H, methyl or ethyl; c is an integerof 0-4; d is an integer of 0-4; a is an integer of greater than 0; b isan integer of greater than 0; and R11 each independently is a covalentbond or a group selected from the following groups:

wherein w and x are each independently an integer of greater than 0; andR12 is —S(O)₂—, —C(O)—, a covalent bond or a substituted orunsubstituted C1-C18 organic group.
 11. The photosensitive polyimideaccording to claim 1, wherein B and D are the divalent organic groupselected from the group consisting of:

wherein y is an integer of 1-12.
 12. A photosensitive composition, whichcomprises, based on the total weight of the composition, at least 1% byweight of the photosensitive polyimide according to claim 1 and at leastone photoinitiator.
 13. The photosensitive composition according toclaim 12, further comprising a reactive monomer or oligomer.
 14. Thephotosensitive composition according to claim 12 or 13, for use in aliquid photo resist composition or dry film photo resist composition.